5 Comments on “Which of the following has an offset field that specifies the length of the header and data?”

1. Shadow says:

   April 15, 2015 at 4:04 am

   “A” ECSAv8 pg. 63

2. Umbra says:

   May 8, 2015 at 3:19 am

   D. TCP Header

   TCP has the data offset field
   http://www.networksorcery.com/enp/protocol/tcp.htm#Data%20Offset
   Data Offset. 4 bits.
   The number of 32-bit words in the TCP header. This indicates where the data begins. The length of the TCP header is always a multiple of 32 bits.

   IP and ICMP don’t carry data. UDP has no offset field since it does hold options.

   1. Mano says:

      July 11, 2015 at 3:08 pm

      A.
      Maybe the word offset is what is confusing here but:
      TCP header has an offset which indicates the length of the header ALONE. i.e. it tells you where the data part starts.
      IP header has a similar parameter (IHL) which tells you the length of the header. But then also has another field (bits 16-31) which tell you the total length of header + data i.e. total size of the IP packet.
      Question asks for offset which specifies length of header and data.
      Hence A.

      1. Mano says:

         July 11, 2015 at 3:09 pm

         and btw, ofcourse IP and ICMP packets carry data – everything that is passed from the stack above i.e TCP segments etc..

3. tcw says:

   September 3, 2020 at 12:57 am

   D is the correct answer according to ECSAv10.

   The TCP header has an Offset field that specifies the length of header and data, whereas the UDP header has a UDP Length field that determines the total size of the UDP packet.